nion form the vena portae, there are visible in
every part of the mesentery other veins, proceeding also from the
intestines, which terminate in glands; and he supposes that these veins
are intended for the nourishment of the intestines themselves. Some of
Galen's contemporaries asserted that upon exposing the mesentery of a
sucking animal several small vessels were seen filled _first_ with air,
and _afterwards_ with milk. They had, doubtless, mistaken colourless
lymph for air; but Galen ridicules both assertions, and thereby shows
that he had not examined the contents of the lacteals. This is somewhat
remarkable, because as a rule he omitted no opportunity of determining
with certainty, by vivisection and experiments on living animals, the
uses of the various parts of the body. As an illustration of this, we
have his correct statement, established by experiment, that the pylorus
acts as a valve _only_ during the process of digestion, and that it is
relaxed when digestion is completed.

He recognizes that the flesh of the heart is somewhat different to that
of the muscles of voluntary motion. Its fibres are described as being
arranged in longitudinal and transverse bundles; the former by their
contractions shortening the organ, the latter compressing and narrowing
it. Such statements show that he regarded the heart as essentially
muscular. He thought, however, that it was entirely destitute of nerves.
Although he admitted that possibly it had one small branch derived from
the _nervus vagus_ sent to it, yet he entirely overlooked the great
nervous plexus surrounding the roots of the blood-vessels, from which
branches proceed in company with the branches of the coronary arteries
and veins, and penetrate the muscular substance of the ventricles. He
endeavoured to prove, by experiment, observation, and reasoning, that
the arteries as well as the veins contained blood, and in this
connection he tells an amusing story. A certain teacher of anatomy, who
had declared that the aorta contained no blood, was earnestly desired by
his pupils, who were ardent disciples of Galen, to exhibit the requisite
demonstration, they themselves offering animals for the experiment. He,
however, after various subterfuges, declined, until they promised to
give him a suitable remuneration, which they raised by subscription
among themselves to the amount of a thousand drachmae (perhaps L30). The
professor, being thus compelled to commence the experim